The CIA released a new report Friday on Iraq's weapons of mass destruction that added little to earlier appraisals but exposed a sharp dispute among U.S. intelligence experts over Saddam Hussein's nuclear weapons program.

WASHINGTON — The CIA released a new report Friday on Iraq's weapons of mass destruction that added little to earlier appraisals but exposed a sharp dispute among U.S. intelligence experts over Saddam Hussein's nuclear weapons program.

The dispute centers on thousands of high-strength aluminum tubes that Iraq allegedly has tried to purchase from foreign suppliers. According to the CIA report, most intelligence experts believe the tubes were to be made into casings for centrifuges that could be used to enrich uranium for nuclear weapons.

But the CIA report notes that some intelligence analysts disagree, arguing that the tubes probably were intended to make conventional weapons, the report said.

Despite the conflicting opinions, President Bush has publicly asserted that the tubes were intended for use in making a nuclear weapon. Speaking on Sept. 12 to the United Nations General Assembly, Bush flatly said the tubes were to be "used to enrich uranium for a nuclear weapon."

A White House report released in conjunction with Bush's speech repeated that unconditional assertion. "Iraq has sought to buy thousands of specially designed aluminum tubes, which officials believe were intended as components of centrifuges to enrich uranium," the report said.

That speech and report marked the start of Bush's aggressive effort to drum up support in Congress and the United Nations for military action if Saddam continued to defy U.N. efforts to discover and destroy his weapons of mass destruction.

Several senior administration and intelligence officials, all of whom spoke only on the condition of anonymity, charged that the decision to publicize one analysis of the aluminum tubes and ignore the contrary one is typical of the way the administration has been handling intelligence about Iraq.

The White House and the Pentagon, these officials said, are pressuring intelligence analysts to highlight information that supports Bush's Iraq policy and suppress information and analysis that might undercut congressional, public or international support for war.

Some U.S. intelligence and military experts dispute the administration's suggestion that Iraq's weapons of mass destruction pose an imminent threat to the United States. One senior military official, speaking on condition of anonymity, said the threat has not increased appreciably beyond what it was when Saddam invaded Kuwait in 1990.

Iraq does have considerable experience with high-speed centrifuges. U.N. inspectors discovered after the 1991 Persian Gulf War that Iraqi scientists, with illicit assistance from German experts, had succeeded in constructing large networks of centrifuges for enriching uranium.

But the administration's assertions about the aluminum tubes provoked considerable debate among nuclear weapons experts. One who reviewed a government analysis of the tubes said he did not believe they were intended for use in Iraq's clandestine nuclear weapons program.

"From what I've seen, this is not conclusive evidence," said the expert, who also spoke on condition of anonymity. He said that the tubes were not suitable for manufacturing into high-speed enrichment centrifuges because their diameters were too small and the aluminum they were made from was too hard.

"It seems to me that the tubes are clearly dual-use, and therefore you cannot conclude they were for uranium enrichment," he said.

David Albright, a physicist and former U.N. weapons inspector, disputed the CIA's assertion that a majority of analysts believe the tubes were intended to help make nuclear weapons.

Albright, the director of the Institute for Science and International Security, a non-partisan think tank, said he has been told that scientists at the Lawrence Livermore National Laboratory in California and other U.S. nuclear weapons facilities disagreed with that assessment but have been ordered not to say anything.

He quoted one scientist as saying that "the administration can say what it wants and we are expected to remain silent."

The publication of the CIA report came as the Bush administration continued pressing its efforts to win resolutions from the Senate and the U.N. Security Council authorizing military force.

The 27-page document said Iraq has large stocks of chemical weapons, has accelerated its efforts to produce biological weapons, including anthrax, and has manufactured missiles capable of hitting targets beyond the 93-mile range permitted by the United Nations.

The report also said that it could take Iraq until the last half of the decade to produce a nuclear weapon if it has to produce its own bomb-grade uranium or plutonium. But if it obtained such materials on the international black market, Iraq could have a nuclear weapon within a year, the report said.